1. Field of the Invention
The present invention relates to a recording device for using thermal energy to eject ink droplets towards a recording medium.
2. Description of the Related Art
Japanese Patent Application (KOKAI) No. SHO-48-9622 and NO. SHO-54-51837 describe ink jet recording devices that apply pulses of heat to ink to rapidly vaporize a portion of the ink and eject an ink droplet from an orifice using the expansion of the vaporized ink.
As described on page 58 in the Dec. 28, 1992 edition of Nikkei Mechanical and in the August 1988 edition of Hewlett Packard-Journal, the simplest method for applying pulses of heat to ink is by energizing thermal resistors, otherwise known as heaters. The common configuration of these conventional heaters includes: a thin-film resistor; a thin-film conductor; an anti-oxidation layer having about 3 .mu.m thickness and formed on these thin films; and an anti-cavitation Ta metal layer having about 0.5 .mu.m thickness and formed on the anti-oxidation layer to prevent cavitation thereof.
Because of the thick protection layers, this configuration requires energy as large as 15 to 30 .mu.J/pulse for ejecting each ink droplet. A large part of this energy is consumed for heating up the substrate.